The obvioud progression I think at this point is Jon to end up going to Dany, ending up becoming her Husband and riding into the north on Rhaegal, named for his ??father??
I think GRRM has reached a point of saturation in terms of his characters. He can't simply off Tyrion, Arya, Jon (dead for keeps) etc until the very end, because there are only two books left.
That isn't really enough time to introduce new main POV characters that the reader is going to grab onto.
I don't think we will see more than maybe or or two MAJOR POV characters to eat it, and a couple secondary POV characters.
That said, all bets are off in the finale.
My expectation is that Dany is Azor Ahai, Jon will be a vehicle to take Melisandra to Dany, as Stanis was a vehicle to take her to Jon. Jon will either seek her out across the narrow sea, or he will meet her when she lands with her army in the final book.
Arya will probably come back into the mix in the final book, having finished her training she will be contracted to kill either Jon or Dany.
How Tyrion figures into this?
Everyone dies and Tyrion climbs his stumpy ass onto the Iron throne